Stoneware teapot with flowers in enamel, UK, ~1850 AD

Saving you a click:

Stoneware is a broad class of pottery fired at a relatively high temperature, to be impervious to water.[2] A modern definition is a vitreous or semi-vitreous ceramic made primarily from stoneware clay or non-refractory fire clay.[3][4] This definition excludes stone vessels that are carved from a solid chunk of stone.

Seems like I’ve seen this beautiful ‘black-background’ style only rarely outside Japanese enameling & glazing. That strikes me as a shame.